heat treatment
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FTIR in Gem Testing | A Pink Sapphire Lesson
A discussion of DRIFTS vs the Beam Condenser FTIR attachment in the testing of pink sapphire. The DRIFTS accessory is generally much better at unmasking heat treatment in ruby and sapphire.
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Gem Treatment Disclosure | Trust
The ethics of gem enhancement disclosure.
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Lecture | Madagascar | Sapphire Isle | Tucson | 6 February 2020
Lotus Gemology's E. Billie Hughes looks at the important sapphire producing localities in Madagascar, along with the key gemological features that can help separate them from other sapphire sources.
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Madagascar Sapphire | Low-Temperature Heat Treatment Experiments
Madagascar has become one of the world’s top sources of fine blue sapphire in recent times. In addition to beautiful untreated material, increasing numbers of treated stones have appeared in the market. Some have been heated to relatively low temperatures, below 1350°C, to lighten their color. To help separate unheated and heated Madagascar sapphire, the authors performed experiments to document the changes they undergo with low-temperature heat treatment in air, which is an oxidizing atmosphere.
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Padparadscha or Pretender | An Unusual Pink-Orange Sapphire
An orangish pink “padparadscha” sapphire was submitted for testing at Lotus Gemology’s Bangkok laboratory. Testing showed a number of conflicting features that suggested the gem was a cleverly treated synthetic pink sapphire designed to imitate natural padparadscha.
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Testing Yellow Sapphire | Passport to Obscurity
The examination of a yellow sapphire provides a lesson in the power of gemological microscopy.